Delineation of relationship between brain tumor and the white matter tracts by means of 3-dimenitional anisotropy contrast imaging and diffusion tensor analysis

目得：为评价三维各向异性对比成像（3DAC）和弥散张量分析在脑肿瘤与白色束关系中的应用价值，我们对5例正常志愿者进行了3DAC成像和弥散张量分析（第一年）和19例幕上脑肿瘤患者。3DAC成像是通过合成彩色编码的扩散加权图像（DWI），通过在3个正交方向上施加运动探测梯度（MPG）获得。使用通过在6个不同方向上应用MPG获得的DWI进行扩散张量分析。利用这些数据集，我们获得了分数各向异性（FA），表观扩散系数（ADC）轨迹和扩散特征值的图像。结果：1）3DAC成像结果在正常人分析中，所有病例的3DAC图像均清晰显示白色物质束。然而，图像往往是穷人在i ...更多信息 在脑肿瘤患者中，我们用3DAC图像评价肿瘤与锥体束的关系。在所有病例中，3DAC图像都能清楚地显示肿瘤压迫神经束或肿瘤/病灶周围水肿累及神经束的关系。2）扩散张量分析结果首先，我们比较了5例正常人和4例脑肿瘤患者的扩散张量分析（FA-3）和传统的3-正交扩散成像（FA-3）测量扩散各向异性的准确性。在正常人的分析中，FA-3的不对称性明显大于FA，在1例脑肿瘤压迫锥体束的病例中，FA-3的不对称性明显被低估，导致错误的结论。测量锥体束的FA、ADC图及特征值。这些指数反映了锥体束的状况，被压缩和/或T2高。结论3DAC成像和弥散张量分析可以提供更多关于白色物质束的有用信息，这可能有助于脑肿瘤的手术计划。少

PURPOSE : To evalutate the usefulness of 3-dimentional anisotropy contrast (3DAC) imaging and diffusion tensor analysis for delineation of relationship between brain tumor and the white matter tracts, we applied these technique to 5 normal volunteers (first year) and 19 patients with a supratentorial brain tumor.METHODS : 3DAC imaging was performed by synthesizing color-coded diffusion-weighted images (DWI) which were obtained by applying motion probing gradient (MPG) in 3-orthogonal directions. Diffusion tensor analysis was performed using DWIs obtained by applying MPG in 6 different directions. Using this data sets, we obtained images of fractional anisotorpy (FA), apparent diffusion coefficient (ADC) trace and diffusion eigenvalues. The FA is one of the indicies representing diffusion anisotorpy.RESULTS :1) Results of 3DAC imagingIn the analysis of the normal subjects, the 3DAC images delineated the white matter tracts clearly in all cases. However, the images tended to be poor in i … More nfratentorial region due to susceptiblity artifacts, which made it almost impossible to evaluation of the fiber tracts in some cases.In the cases with brain tumor, we evaluated the relationship between a tumor and the pyramidal tract by 3DAC images. In all cases, 3DAC images could clearly show the relationship ; the tumor just compressed the tracts or the tumor/perifocal edema involved the tracts.2) Results of diffusion tensor analysisAt first, we compared the accuracy of the measurement of diffusion anisotropy between diffusion tensor analysis (FA) and conventional 3-orthogonal diffusion imaging (FA-3) in 5 normal subjects and 4 patients with brain tumor. In the analysis of healthy subjects, FA-3 was significantly more asymmetric than FA.In one case with a brain tumor compressing the pyramidal tract, FA-3 showed markedly underestimated, which led erroneous conclusion.Then, we investigated the diffusion characteristics of the pyramidal tract in cases with brain tumor. The FA, ADC trace and eigenvalues of the pyramidal tracts were measured. These indices reflected condition of pyramidal tract, being compressed and/or being T2-high. Estimation of eigenvalues, in addition to the FA and the trace, should provide more detailed information.CONCLUSION3DAC imaging and diffusion tensor analysis may provide additional useful information about the white matter tracts, which may be helpful for surgical planning of brain tumors. Less